Disable Rails SQL logging in console

How to temporarily disable SQL logging

When you need a temporary break from SQL logs—maybe for debugging—you can cocoon your code in a block:

ActiveRecord::Base.logger.silence do
  # Your noise-free operations
end


This maneuver lets you enjoy quiet during operations and resume normal logs afterwards.

Navigating the silence

Resuming logging without a hitch

Here's how to get the logs back (spoiler alert: it's pretty straightforward):

old_logger = ActiveRecord::Base.logger # This is our trusty logger
ActiveRecord::Base.logger = nil # Shush! We're doing science!

# Silent operations go here...

ActiveRecord::Base.logger = old_logger # Back to our regular programming


With this neat little trick, you can slip in and out of silence like a ninja.

Commanding the log level

Control the chatter with the logger's level:

ActiveRecord::Base.logger.level = Logger::INFO # or whatever level suits your mood.


Just like adjusting volume, but for logs.

Configuring the logger in development

In config/environments/development.rb, config.after_initialize provides a nifty handle for logging:

config.after_initialize do
  ActiveRecord::Base.logger = nil if Rails.env.development?  # Developers deserve peace too!
end


Think of it as a personal butler managing your logs.

Avoiding a null faux-pas

Setting the logger to nil might cause a mess; Rails can be a drama queen if expected items go missing. To avoid logger.warn errors:

ActiveRecord::Base.logger = Logger.new('/dev/null')  # No logger no cry


This safely reroutes logs to the belly of the beast (i.e., Unix blackhole), keeping Rails drama-free.

Making ActiveSupport::LogSubscriber go stealth-mode

When subtlety is key, try overriding ActiveSupport::LogSubscriber. It's the SQL log raconteur that you never knew you could silence:

module ActiveSupport
  class LogSubscriber
    def debug(*args, &block)
      # Gags the SQL logging, effective silence ensues!
    end
  end
end


Mum's the word!

Splitting the logger

If you need to see other ActiveRecord logs but keep SQL hushed, consider cloning the logger:

sql_silent_logger = ActiveRecord::Base.logger.clone
ActiveRecord::Base.logger.level = Logger::ERROR # Mute SQL logs
# Your operations go here...
ActiveRecord::Base.logger = sql_silent_logger # Back to the reality show


With this, SQL logs can take a nap while the rest of the logs party on!

Disabling SQL logging in Rails 4

In Rails 4, disabling SQL logging is a breeze:

config.active_record.logger = nil  # Rails 4's gift to mankind


The SQL gods can finally rest...